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NACA-RM-L55L14
Preliminary measurements of the aerodynamic yawing derivatives of a triangular, a swept, and an unswept wing performing pure yawing oscillations, with a description of the instrumentation employed
Year: 1956
Abstract: The advent of high-speed airplanes of high relative density has focused attention on certain problems associated with the dynamic stability of aircraft which, because of previous unimportance, have here-to fore been neglected. Among the problems are the effect of periodicity of the airplane motion on the stability derivatives, and the possibility that acceleration derivatives (which generally have been neglected when making dynamic stability calculations) may be important for certain airplane configurations.
Some information of both problems already has been obtained experimentally. References 1 through 3, for example, show comparisons between damping-in-yaw derivatives obtained from steady-state tests performed by use of the Langley stability tunnel curved-flow technique and from tests in which the models were oscillated about their vertical axes. The former technique permits measurements of the derivatives due to yawing velocity for example the yawing moment due to yawing velocity cnr. The latter technique permits measurement of a combination of damping derivatives (cnr,w-cnβw). A comparison of results from the two techniques for the same model under indetical conditions indicates the approximate magnitude of the sideslip acceleration derivative cow. Such comparative test have indicated that for certain configurations the derivatives associated with acceleration in sideslip can be quite large at high angles of attack. Direct measurement of the sideslip acceleration derivatives (reference 4) have, of course, substantiated the results of the comparative tests.
There is little experimental data available on the effect of motion periodicity on aerodynamic derivatives associated with linear or angular velocity. Recent test on a series of wings performing lateral plunging oscillations across the jet of a tunnel (ref.4) have permitted evaluation of the derivatives associated with sideslip velocity during a sinusdelta and a 45 sweptback wing at high angles of attack the sideslip derivatives extracted from lateral oscillation tests were much different from the derivatives obtained by the usual stead-state wind-tunnel procedures.
As a continuation of the program to determine effects of motion periodicity on the various stability derivatives, the present investigation was made to determine the derivatives associated with yawing velocity and yawing acceleration by use of an apparatus which simulated a pure yawing oscillation. Data also were obtained from steady-state yawing tests by use of the Langley stability tunnel curved-flow technique for comparison with the oscillation data.
Some information of both problems already has been obtained experimentally. References 1 through 3, for example, show comparisons between damping-in-yaw derivatives obtained from steady-state tests performed by use of the Langley stability tunnel curved-flow technique and from tests in which the models were oscillated about their vertical axes. The former technique permits measurements of the derivatives due to yawing velocity for example the yawing moment due to yawing velocity cnr. The latter technique permits measurement of a combination of damping derivatives (cnr,w-cnβw). A comparison of results from the two techniques for the same model under indetical conditions indicates the approximate magnitude of the sideslip acceleration derivative cow. Such comparative test have indicated that for certain configurations the derivatives associated with acceleration in sideslip can be quite large at high angles of attack. Direct measurement of the sideslip acceleration derivatives (reference 4) have, of course, substantiated the results of the comparative tests.
There is little experimental data available on the effect of motion periodicity on aerodynamic derivatives associated with linear or angular velocity. Recent test on a series of wings performing lateral plunging oscillations across the jet of a tunnel (ref.4) have permitted evaluation of the derivatives associated with sideslip velocity during a sinusdelta and a 45 sweptback wing at high angles of attack the sideslip derivatives extracted from lateral oscillation tests were much different from the derivatives obtained by the usual stead-state wind-tunnel procedures.
As a continuation of the program to determine effects of motion periodicity on the various stability derivatives, the present investigation was made to determine the derivatives associated with yawing velocity and yawing acceleration by use of an apparatus which simulated a pure yawing oscillation. Data also were obtained from steady-state yawing tests by use of the Langley stability tunnel curved-flow technique for comparison with the oscillation data.
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| contributor author | NASA - National Aeronautics and Space Administration (NASA) | |
| date accessioned | 2017-09-04T17:58:32Z | |
| date available | 2017-09-04T17:58:32Z | |
| date copyright | 01/01/1956 | |
| date issued | 1956 | |
| identifier other | FRSWXDAAAAAAAAAA.pdf | |
| identifier uri | http://yse.yabesh.ir/std;jsery=autho162s7D8308/handle/yse/181631 | |
| description abstract | The advent of high-speed airplanes of high relative density has focused attention on certain problems associated with the dynamic stability of aircraft which, because of previous unimportance, have here-to fore been neglected. Among the problems are the effect of periodicity of the airplane motion on the stability derivatives, and the possibility that acceleration derivatives (which generally have been neglected when making dynamic stability calculations) may be important for certain airplane configurations. Some information of both problems already has been obtained experimentally. References 1 through 3, for example, show comparisons between damping-in-yaw derivatives obtained from steady-state tests performed by use of the Langley stability tunnel curved-flow technique and from tests in which the models were oscillated about their vertical axes. The former technique permits measurements of the derivatives due to yawing velocity for example the yawing moment due to yawing velocity cnr. The latter technique permits measurement of a combination of damping derivatives (cnr,w-cnβw). A comparison of results from the two techniques for the same model under indetical conditions indicates the approximate magnitude of the sideslip acceleration derivative cow. Such comparative test have indicated that for certain configurations the derivatives associated with acceleration in sideslip can be quite large at high angles of attack. Direct measurement of the sideslip acceleration derivatives (reference 4) have, of course, substantiated the results of the comparative tests. There is little experimental data available on the effect of motion periodicity on aerodynamic derivatives associated with linear or angular velocity. Recent test on a series of wings performing lateral plunging oscillations across the jet of a tunnel (ref.4) have permitted evaluation of the derivatives associated with sideslip velocity during a sinusdelta and a 45 sweptback wing at high angles of attack the sideslip derivatives extracted from lateral oscillation tests were much different from the derivatives obtained by the usual stead-state wind-tunnel procedures. As a continuation of the program to determine effects of motion periodicity on the various stability derivatives, the present investigation was made to determine the derivatives associated with yawing velocity and yawing acceleration by use of an apparatus which simulated a pure yawing oscillation. Data also were obtained from steady-state yawing tests by use of the Langley stability tunnel curved-flow technique for comparison with the oscillation data. | |
| language | English | |
| title | NACA-RM-L55L14 | num |
| title | Preliminary measurements of the aerodynamic yawing derivatives of a triangular, a swept, and an unswept wing performing pure yawing oscillations, with a description of the instrumentation employed | en |
| type | standard | |
| page | 36 | |
| status | Active | |
| tree | NASA - National Aeronautics and Space Administration (NASA):;1956 | |
| contenttype | fulltext |